To resolve the problem in which: in a conventional power generating facility that use of moisture-rich fuel (ultra moisture-rich combustible material) may cause an output reduction or efficiency reduction of the Rankine cycle (steam turbine cycle) and a reduction of boiler efficiency due to the occurrence of heat loss caused by fuel-containing moisture becoming over-heated steam and being discharged into the surrounding atmosphere.

Solar heat steam generated through utilization of solar heat with a solar heat steam generating unit and low temperature steam of low availability are utilized to heat moisture-rich combustible material (fuel) at a steam heat dryer, and dry the material (evaporate and over-heat contained moisture), or further potential heat of moisture-rich evaporated steam is recovered with the moisture-rich evaporated steam potential heat recovering unit, the recovered heat is utilized for heating and drying the fuel with a regenerative dryer, and the dried fuel is applied as fuel for power generating facilities to cause the ultra moisture-rich combustible material deposited in the prior art to be available as fuel so that the power generating facilities contribute to conserve fuel resources and global environmental protection.